Main technical performance and use method of precision acidity meter (PH meter)
1. Overview of Precision Acidity Meter (PH Meter)
Acidity meter (PH meter) is a high-performance, high-precision multi-function digital display PH meter. It adopts LED digital display. It has the advantages of stability, reliability, and ease of use. It is widely used in health care, pharmaceuticals, universities, scientific research units, industrial and mining Corporate and environmental protection departments.
The characteristics of PHS-3D series acidity meter (PH meter) are as follows:
1. LED digital display;
2. Manual temperature compensation;
3. Two-point calibration.
Second, the main technical performance of precision acidity meter (PH meter)
1. Measuring range: pH: 0 ～ 14.00pHmV: 0 ～ ± 1999.9mVT ℃: 0 ～ 99.9 ℃
2. Resolution: pH: 0.01pHmV: 0.1mVT ℃: 0.1 ℃
3. Accuracy: pH: ± 0.01pHmV: ± 0.1% (FS) T ℃: ± 0.5 ℃
4. Input impedance: ≥1 × 1012Ω
5. Temperature compensation range: 0 ～ 99.9 ℃
6.Dimension: 206mm × 180mm × 72mm
7. Weight: 1.5kg
8. Normal conditions of use:
⑴Ambient temperature: 0 ～ 40 ℃
⑵Relative humidity: ≤85%
⑶Power supply: AC (220 ± 22) V; (50 ± 1) Hz
â‘· No significant vibration and electromagnetic interference
3. Principle of Precision Acidity Meter (PH Meter)
The precision acidity meter (PH meter) uses a plastic shell composite electrode composed of a measuring electrode and a reference electrode as a pH measuring electrode. When the hydrogen ion activity in the solution changes, the electrode electromotive force also changes accordingly. The change of electromotive force conforms to the following formula:
E = E0-2.3026RT / F × pH
Among them: R--gas constant [8.314J / (mol · K)]
T--absolute temperature [(273.15 t ℃) K]
F--Faraday constant (9.648 × 104C · mol-1)
E0--zero potential of electrode system
pH--Indicates the pH value of the measured solution
By measuring the change value of the electromotive force, the pH value of the measured solution is obtained.
Fourth, the use of precision acidity meter (PH meter)
1. Preparation before measurement
1) Install the composite electrode on the electrode rod, and insert the electrode plug into the measuring electrode socket at the rear of the instrument.
2) Connect the temperature sensor to the sensor socket (if manual setting is required, there is no need to connect the sensor).
3) Rinse the electrode with distilled water.
2. pH calibration
Because the zero potential conversion coefficient of each electrode is different from the theoretical value, and they are different. Therefore, to measure the pH value, the electrode must be pH calibrated.
1) Temperature setting. Press the "temperature setting" key to make the temperature indicator in the temperature setting position, at this time the first digit of the display flashes, use the "→" key to move the setting position, and at the same time, press the "↑" key to make the temperature display value be Measure the temperature value of the standard solution at this time, and then press the "OK" button to confirm.
2) After the electrode is washed with distilled water, blot it dry with filter paper, then put the electrode into the first standard solution, press the "pH / pH calibration" key to put the instrument in the pH measurement state, and then press "pH" after the reading is stable. / pH calibration "key, make the instrument in the pH calibration state, and press the" → "" ↑ "key to make the display value is the pH value of the standard solution at the current temperature. Press the "OK" button again to confirm.
3) After washing the electrode with distilled water, blot it dry with filter paper. Put the electrode in the second standard solution (select a standard solution with a similar pH value according to whether the sample solution to be measured is acidic or alkaline, and the difference between its pH value and the first standard solution should not exceed 3 pH units), Press the "pH / pH Calibration" key to put the instrument in the pH measurement state. After the reading is stable, press the "pH / pH Calibration" key to put the instrument in the pH calibration state, and press the "→" "↑" key to make the display value At that time, the pH value of the standard solution, then press the "Confirm" button to confirm.
2) Set the temperature according to the temperature setting method in pH calibration, so that the temperature value is the temperature of the measured sample at this time.
3) Press the "pH / pH Calibration" key to make the "pH" indicator light on, and stir the solution with a glass rod to make it uniform. After the reading is stable, the displayed value is the pH value of the sample being measured.
4. Measurement of electrode potential (mV) value
Place the electrode in the measured solution and press the "mV" key, the "mV" indicator lights. Stir the solution to make it uniform. After the reading is stable, the displayed value is the electrode potential "mV" value of the solution, and the polarity is automatically displayed.
4) The instrument calibration is completed.
3. Determination of pH
1) After cleaning the electrode with distilled water, wash it with the test solution twice more, and place the electrode in the test solution.
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